write#

hollerith._writer.write_int_to_buffer(buffer, int value, int width)#

Writes a string representing the int value to buffer within the given width, right justified.

Parameters:

buffer: Buffer to write to - it could be a file or a StringIO object, for example. The only requirement is that it must contain a write attribute that is callable with a single string argument.
valueint: Integer to write. This could also be a numpy.int32
widthint: The number of characters to write

Examples

>>> import io
>>> import hollerith as holler
>>> buffer = io.StringIO()
>>> holler.write_int(buffer, 145, 16)
>>> print(buffer.getvalue())
    '             145'

hollerith._writer.write_float_to_buffer(buffer, double value, int width)#

Writes a string representing the float value to buffer within the given width, right justified.

Parameters:

buffer: Buffer to write to - it could be a file or a StringIO object, for example. The only requirement is that it must contain a write attribute that is callable with a single string argument.
valuefloat: Float to write.
widthint: The number of characters to write

Examples

>>> import io
>>> import hollerith as holler
>>> buffer = io.StringIO()
>>> holler.write_float(buffer, 1.0, 16)
>>> print(buffer.getvalue())
    '             1.0'

hollerith._writer.write_string_to_buffer(buffer, unicode value, int width)#

Writes a string representing the string value to buffer within the given width, left justified.

Parameters:

buffer: Buffer to write to - it could be a file or a StringIO object, for example. The only requirement is that it must contain a write attribute that is callable with a single string argument.
valuestr: String to write.
widthint: The number of characters to write

Examples

>>> import io
>>> import hollerith as holler
>>> buffer = io.StringIO()
>>> holler.write_string(s, "hello", 16)
>>> print(buffer.getvalue())
    'hello           '

hollerith._writer.write_null_to_buffer(buffer, int width)#

Writes width space characters to buffer

Parameters:

buffer: Buffer to write to - it could be a file or a StringIO object, for example. The only requirement is that it must contain a write attribute that is callable with a single string argument.
widthint: The number of spaces to write

Examples

>>> import io
>>> import hollerith as holler
>>> buffer = io.StringIO()
>>> holler.write_spaces(buffer, 16)
>>> print(buffer.getvalue())
    '                '

hollerith.write_table(buffer, table: DataFrame, numrows: int, spec: List[Field])#

Write table to buffer with fixed width columns

Parameters:

buffer: Buffer to write to - it could be a file or a StringIO object, for example. The only requirement is that it must contain a write attribute that is callable with a single string argument.
tablepandas.DataFrame: Table to write.
numrowsint: The number of rows to write. This might be larger than the length of table. If so, append with empty lines with the right size.
specList[hollerith.Field]: Specification of the table. Must be the same length as the number of columns in table.

Notes

Here, we convert the table to a numpy 2-d array with a type of object in order to call write_numpy_table. Numpy arrays of a narrower type are possible, such as arrays of ints or floats, and this conversion can be expensive. A future optimization would be to expose Cython-level methods in _writer.

Examples

>>> import io
>>> import hollerith as holler
>>> import pandas as pd
>>> buffer = io.StringIO()
>>> spec = [holler.Field(float, 20), holler.Field(float, 20)]
>>> table = pd.DataFrame({"a": [1.0, 3.0, 5.0], "b": [2.0, 4.0, 6.0]})
>>> result = holler.write_table(buffer, table, 3, spec)
>>> print(buffer.getvalue())
    '             1.0                 2.0
                  3.0                 4.0
                  5.0                 6.0'